The capturing of biomarkers in a patient's body is useful for diagnosing and locating lesions such as tumours. Biomarkers are molecules e.g. proteins which are specific to the lesion under consideration. For example the ACTH protein is a biomarker of pituitary corticotrope adenoma or Cushing's disease.
Before or during surgical procedure on the lesion, it is generally necessary to identify with precision the contours of this lesion, so that it can be entirely removed without removing healthy tissue. The capture of biomarkers pre- or per-operatively is currently the subject of experimental studies for some surgical procedures. For example, mention may be made of intra-cranial molecular biopsy by stereotaxy for the diagnosis of gliomas. This procedure consists of inserting in the patient's head, via a stereotactic frame, a stylet provided at its distal end with an activated silicon wafer to capture the molecule(s) to be identified. Since this technique assumes the passing through several tissues, it is necessary to protect the silicon wafer against any contamination aside from the lesion itself.
It has therefore been proposed in document WO 2006/090220, to provide a guide enclosing the stylet and allowing the sliding and rotation of the stylet within the guide. The guide, at its distal end, has a window formed of an opening made in the wall thereof. When being inserted through the skull, the stylet is positioned in the guide so that the activated side of the silicon wafer lies opposite the window, thereby being protected. When the tip of the guide has reached its target, the surgeon rotates the stylet through about 180° so that the activated side of the silicon wafer is exposed. After the time required for capturing the molecules, the surgeon again rotates the stylet through about 180° within the guide, so that the activated side of the silicon wafer is again protected for the return pathway of the stylet.
However, this instrument has limitations, in particular in terms of volume and use. The need to arrange a guide around the stylet effectively increases the volume of the instrument. The outer diameter of the instrument inserted in the tissues is therefore of the order of 2 to 5 mm.
In addition, it cannot be used for the treatment of some pathologies, in particular for the detection of pituitary adenoma (or Cushing's disease). The pituitary gland is located at a point which would require the perforating of several particularly sensitive organs in order to have access thereto via this route. Also, since it is desired to capture the ACTH protein for more precise location of the lesion, with a view to removal during the same surgical procedure, the stereotactic approach described in the above-mentioned document is of little interest.
At the current time it is also known to perform one or more extemporaneous biopsies, by removing tissues from the regions of interest of the organ under consideration for the purpose of analysis during surgery. However, this technique is aggressive. On the contrary, it is sought to use minimally invasive procedures.
It is therefore the objective of the present invention to provide an instrument for minimally invasive molecular capture allowing the replacement of biopsy via stereotactic route when this cannot be envisaged, that is particularly suited for intra-pituitary sampling. It is a further objective of the invention to provide an instrument of smaller volume than in the prior art.